July 8, 2024
Recognizing the importance of BSD in Apple’s success helps us better appreciate the value of open source contributions in shaping the technology we use daily.

Consider this: Apple’s stylish and user-friendly devices, like the powerful MacBook and the ubiquitous iPhone, owe much of their reliability and performance to an open source operating system. But which open source OS do they use? Although it’s often claimed that Apple’s macOS, iOS, iPadOS, watchOS, visionOS and tvOS are directly descended from FreeBSD, this is actually a misconception.

The true foundation of these operating systems lies in a marriage between Apple’s older OS technologies and NeXTSTEP, which is itself a hybrid of Mach and BSD, predating FreeBSD. While some elements of the FreeBSD userspace were incorporated into these operating systems over the years, the Apple kernel (XNU) does not directly stem from FreeBSD. However, they do share a common BSD heritage.

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